W8CMN UHF DMR Network / Mi5
CMEN has built Michigan’s largest Digital Voice network and the First DMR/MotoTRBO network. CMEN is know for having the first P25 Digital Voice repeater on the air in the state in 2002.. Well before DSTAR was even a thought. We already have full network coverage in over 15 Michigan Counties. Wayne, Oakland, Macomb, St. Clair, Genesee, Shiawassee, Livingston, Washtenaw, Jackson, Ingham, Eaton, Clinton, Calhoun, Kalamazoo and Barry, with additional sites being added!
DMR is a ETSI Standard and we are using Tier II. Tier II specifies two slot TDMA in 12.5 kHz channels. There are currently many manufactures producing DMR compliant subscriber radios. The two slot TDMA allows us to have what acts like 2 different repeaters/talk paths/slots per RF frequency/equipment. These slots allow different uses with one set of gear at a tower site. Our sites are all IP linked together allowing a type of Roaming currently not see in other amateur gear/modes. When radios are programmed properly for our system/network the user just selects the talk-group they want to use and the radio determines which tower site to use. This is done in a passive manner so the subscriber radio does not transmit unless a user keys the radio. Users are also presented with a channel grant/deny tone when they key the radio. This lets the user know if they are into the repeater or not. Also prevents multi-key overs of other users.
We are currently using Motorola’s MotoTRBO line of base station equipment. These base stations have IP SiteConnect built into them. Which allows linking of sites over the internet or any IP network. While we are using internet connections at the moment we have started building out a private licensed microwave network between sites so as to not rely upon the internet for instate linking. The internet can fail our digital voice network will still keep going.
We do ask that all users on the network request a radio ID from DMR-MARC. This helps from users just picking random numbers and causing issues with the network. You may contact any of the CMEN Trustees if you need help programming any of your radios but please note that programming takes time and we have standard templates already setup for most of the manufactures gear. We can make small changes on a case by case basis
If you are looking for equipment it does come up from time to time on eBay Looking for the Motorola XPR6550,6500,4550,4350,6350 line of radios. Hytera PD782G and MD782G are great choices.
If you are wanting to purchase new the following vendors are great to deal with:
Jeff @ Sandys Communications firstname.lastname@example.org sandyscomm.com